Frequency spectrum resources are resources of extreme importance in radio communication, and are a factor that affects the cost of an operator. Therefore, all operators want to improve frequency spectrum utilization as much as possible on the basis that user experience is almost not affected.
For example, for a UMTS (Universal Mobile Telecommunications System, Universal Mobile Telecommunications System) system or a DC-HSDPA (Dual-Cell High Speed Downlink Packet Access, Dual-Cell High Speed Downlink Packet Access) system, frequency spectrum utilization may be improved by reducing the spacing between carriers. However, during the implementation of the present invention, the inventors find that because the spacing between carriers is narrowed, interference between the carriers is increased, and call quality for users is deteriorated, resulting in poor user experience.